The invention relates to a method of transmitting serial data structures in information carrier (hereinafter "transponder") identification systems and a non-contacting electromagnetic transmission system operating in accordance with the method. Furthermore, it relates to a transponder suitable for the method and system.
Identification systems of the wireless type are known, particularly in chipcards and tool identifiers as disclosed in German Patent Specifications Nos. 3 72 18 22, 3 72 16 22, European Patent EP 79 047 and in WO 88/03594. The known identification systems use integrated chips on the transponder side and are disadvantageous because a register for comparing data dissipates energy and comparatively high energy levels are required for data transfer.
Furthermore, a comparatively low level of data security exists and, with respect to some applications, the time required for data transfer and data comparison is comparatively high.